Hey, I as many other before me, have been linked up to this thread, I've been reading it since there were about 7 pages or so, and figured I'd contribute to it.
I drive an 87 Honda CRX (ack! an import, I know, but it works, and is cheap on gas:p) My cars already a light gray/silver so I was deadset on getting a silver colour so the engine bay still looks fine. The tremclad aluminum stuff, which I had some extra of from another project is useless, as the pigment comes out when you touch it and you cannot topcoat it with any other products, as they use actual aluminum in it, which has strange properties (to warn anyone who was/is planning on using it).
I looked around and found another line of paints called Stop Rust (or something to that effect) made by beautytone for HomeHardware, this stuff is even cheaper then the Tremclad is too, and works just as well (talked to a paint guy who uses it on his cars). The Stop Rust comes in an aluminum colour that is topcoatable and durable, I let it dry overnight in about 2 degree conditions(Celcius, I'm Canadian eh), I recoated again the next night, the next morning I couldnt scratch it with my fingernail or my well worn car key (it doesnt have sharp edges). This stuff might be the jackpot, plus here its 26 bucks for a gallon, vs 36 for the tremclad
I've located a roll-on clearcoat as well, made for automotive use, so its uv resistant, clear (not yellowish), and most importantly very durable.
Its called Crystal Coat by Zero Rust and costs 32 dollars(canadian) a quart, (so the clearcoats costing me twice as much as the paint).
Once I'm done school for the year (the end of april) I'll be painting my entire car and get some pictures up. I figured some of the people on here might be attracted to the roll-on clearcoat, since its very difficult to find. This will eliminate alot of wetsanding as well, since you only take it down to 600 grit then clear it.
anyways that's all for now folks, thanks for all the useful info!