I mentioned something like this in a thread on UCD... It was really in-depth. I'll copy and paste it if I can find it again...
Ok, Here's the direct copy-and-paste... it's a little off-topic, and more about what kind of cars are purchased where, but it gets into tuning and trading as well.
"Ok, I've looked through this thread, taken most opinions in to consideration, and thought up something I, and likely many others will think is cool.
*Disclaimer - there should NOT be standard cars. It is unacceptable (for PD, anyways), to have content that is not as thorough as other content. That is my biggest issue with GT5. Not many games have items that are more poorly designed or modeled than others, let alone major first-party developers.* - Rant over.
As stated, no standard cars. All high-res. And I think ALL cars, should be able to be found in the used car dealership, with some exceptions.
- Cars with a very modern year - models within 3-5 years of the current date (so it could change over time - an interesting feature. There may be issues with people using offline clocks, though...) will be unlikely to show up, as they aren't likely to be sold.
- For those online, cars will always be sold through this dealership, as is - mileage, damage, installed parts, etc. You can remove what parts you want before selling - maybe even keep functional parts from a mostly destroyed car, and use those to fix another. Sell damaged ones as scrap or something. The parts bit is a bit extreme, but seems somewhat interesting - it could build up the tuning and trading community.
- In addition, those online could purchase your car or parts in the dealership. Offline, you could find cars in various states of tuning or disrepair. Those that are damaged can be significantly reduced in price - this would make buying your first cars easy, or finding a run-down super car more efficient if you have parts to fix it up.
- Any cars purchased in career/GT mode will be immediately unlocked in Arcade/online mode stock, and all of your personal cars can be use at any time without affecting how they act in career (say if some kid smashes your car online - it won't affect you). That or all or most cars will be ready for use, maybe with the addition of an ability to set a price range for tuning online. Basically a budget for tuning, allowing limitations. I know people have wanted certain restrictions for tuning, and this may help.
- Multiple dealers. Special shops for rare/classic cars - it cycles like the used dealership, but has much more rare cars, all in top condition, and very expensive. It should be easy enough to find just about any rare car in one sitting. A race car dealer ship... Kind of self-explanatory. Of course the NCD. The UCD would contain mostly road cars, but have low chances of rare cars. This would allow much cheaper ways of coming by rare cars. Concepts I'm not sure of... But maybe a separate dealership for them. Maybe online auctions or competitions, or gift cards.
- It would be cool for the OCD to allow you to sell your car there, and anyone to purchase it. If there is a livery editor and you sell a car, it would be nice to have a set gamer tag to the original owner, so one won't take credit for others art/tunes. Prices for selling and buying would depend on what parts you sell with, and what condition it's in; maybe livery.
- For offline, it could be cool if you could sell and "re-purchase" your own cars after an "AI player" buys your car. that or maybe separate accounts on the system could interact with another.
Summary:
-Multiple dealerships - all cars should have a chance to be purchased within a day of play for full or reduced price, all at top condition.
-Cars purchased in career can either affect or have no affect on what you have access to online or in Arcade.
-You can sell and re-purchase cars to a dealership, maybe parts as well.
-Online you can purchase other cars with tuning.
-Modern, concept, and rare cars are unlikely to show up as used.
Extreme and unlikely ideas:
-You can scavenge off of "junked" cars (which are very cheap) and use those parts to repair others. Tis cold be a cheaper way of coming by a super car or race car.
*The parts system is something that would have to be introduced, but if it was, it would make the UCD ideas much more interesting."
