This may just be me, but I would have appreciated if you'd said up-front that you were planning this as a business endeavor.  Nonetheless, I am interested to see what you come up with.

This looks quite interesting.  I would enjoy reading a detailed write-up if you are planning on making one.  I assume you are storing sprite data on the EEPROM and that this is copied to the Propeller's internal RAM on boot?  If so, is the Z80 involved in this process, or does the Propeller access the EEPROM directly?  Also, does your Cartridge ROM also contain your bootloader, or do you have a separate boot ROM?  I am aware this is off-topic for this thread, so you may wish to start a separate thread about this project.

Thanks guys for all of your input.

To tell a little bit more about myself, I'm starting an electronics business and I'm thinking of starting points; areas where I can begin. I am interested in video games, music, computers, and robotics (to say the least) and I'm just thinking of start-up projects that people would actually buy.

I am 100% willing to build anything computer electronics related. You should check out the 8-bit console I built recently.

http://imgur.com/gallery/VZRax

Thanks again for your input guys.

Oh my god I love it.

If someone could make something like this, that would be pretty swell.
http://www.youtube.com/watch?v=NV6IFOVY-go

What's the point of being "true" if you're gonna mix chips anyway? I think you should make something "new" instead. Maybe something like a keyboard so that people can make live chipmusic?

I want something that does everything from nes to c64 to snes to genesis all in one synth. That would be really cool, especially if it could do all at once

Like, a hard synth that has all of the different chips from each packed into it and can utilize all of them.

Yeah it's called a computer m8 lol

One thing that would be useful to me, personally, is simply a midi box with sockets for whatever sound chip you feel like using.  I like the various limitations and quirks of various platforms, but I dabble in all of them and would love to be able to record on all of them. A box like this could offer the ability to compose using multiple chips or record with specific platforms in mind.  This would allow one person to stay true to the hardware while another person with the same box could compose for multiple platforms at the same time.  If I could not require a million different platforms just to attain the authenticity I craved, that would be worth at least the amount I've spent on my Gameboys.

intimidated?
gameboys always frightened me...

Like the keyboard everyone pretended Crystal Castles had.

The limitation really is a huge idea-catalyst. But you'll find that it's inevitable that a lot of people turn to DAWs in chipmusic. I feel guilty (chip guilt?) when I try layering DAW stuff on top of 1xlsdj. But it's become kind of universally panned to be a 'purist' about chipmusic at this point because it doesn't really contribute anything, so...

My fantasy idea would be something very like what you want, though too crazy to build most likely. I would be a synth keyboards that has real chips on board being used as oscillators. Like switchable between modes like SID mode or 2a03 mode or POKEY mode. I could do cool stuff like route the 2a03 through the SID filter and would have on board routable LFOs and envelopes for controlling the chips. Kinda like MSSIAH and MidiNES stuffed into an all in one hardware synth.

Personally I feel that dedicated all-in-one solutions are conceptually in conflict with (at least a subset of) Chiptune as a way of music creation. For me, it is the limitations of using old hardware designed for playing video games (not designed for making Chiptunes) that gives much Chiptune music a great deal of its character.  This applies to me both as a listener and as an LSDJ user. I enjoy it when I can listen to a piece of music and think, "Wow, was that really 1xLSDJ?"  I have also heard here frequently that it is this same limited environment which provides (or augments) many artists' ability to be creative. While I have nothing against new electronic instruments, to me they wouldn't really be Chiptune, in the same way that, say, an analogue synth or a DAW isn't Chiptune.

That being said, I think there is a market within the Chiptune community for new and innovative hardware / software projects that push the limitations of the hardware we use, although such projects have been met with a variety of opinions.  For example the Ninstrument Synthboy has been somewhat controversial, while the Arduinoboy has been generally well-received (notwithstanding the confusion of some new users about the many modes).  I think staying true to the spirit of Chiptune is important, but also being part of the community in addition to wanting to give something to the community.

a laptop with Plogue Chipsounds?  Cause yeah it's got it all covered, and covered well.

Hey BitCruncher, I have a fairly simple but wildly useful project that you may want to tackle.  It's a software utility and could be a good way to get your feet wet in the current chip scene.  PM me if you're interested!