how about a sharpie?  thats how I paint my hand launch gliders.  might take awhile.

Dennis,
the answer to this I think really lies in the topcoat. There are many products that are ok to put color on the airframe. The secret lies in the clear. For my experience, I dont think that there is really anything out there that will give us the gloss and holdout that urethane clear will. Its simpler, stronger, more durable than laquer, and it doesnt shrink out either. There are now waterbased Urethanes now coming out, but I wouldnt want to explore them till they have been around. so long story short, yes we dont need fuel proofing, but we still need durable and tough and shiney,, nope Urethane clear still gets my vote . the topcoat and primer is wwhere the weight is. So I dont see any real gains to be had.

If Urethane clear is sprayed with the correct solvents and applied carefully, there is virtually no need to buff it out at all. The exception being to remove small dirt nibs and minor flaws. Urethane does not "die back" or dull like dope does as it dries. It is entirly possible to spray your model in a clean room, and find no need to polish at all! This of course is contingent upon proper application and product use. Dope is virtually impossible to spray and obtain a suitable gloss that will hold out over time due to the nature of the product.
 as to polishing Urethane, My strongest reccomendation is to accomplish polishing that may be required within three to four days, no longer. Any longer than that and the surface becomes so hard as to make it very very difficult to remove the sanding scratchs with polishing. I also use very fine paper, 1500 is the coursest , to sand the flaws before polishing. Use a polish that is engineered for Urethane clears. Not Brasso, or any of the other snake oils that are commonly used for Dope.

I tried using water based urethane on a balsa skinned sailplane - had a devil of a time with it.  The water in the varnish kept making the balsa expand; sand it smooth (exposing at least some balsa and it would expand again with the next coat. eventually I sort of got it under control but I will never do it that way again.

Are there any other non-dope and no smell products that will work for balsa prep? 

well I am familiar with automotive clears. The current ones are all pretty water clear. Older ones like deltron , had a tinge to them. The new stuff, at least that I use ,, is crystal clear,,, I use PPG 2042, Randy uses Omni and seems to like it pretty well. I cant say as to its clarity but I am fairly certain its pretty good.
The way to tell is to take the lid off the can and look into the dclear. you can tell how much yellow it has.

As for water Urethanes, as in woodworking urethanes? They really arent made for what we are doing, I dont have anything to say about them. some people use them, I have no interest in exploring them for the reasons stated

When comparing Dope to Urethane, you need to remember that Dope is only about 12 percent solids,, and urethanes are typcially 40 to 50 percent solids. So you have to put on like 5 coats of dope to equal one coat of Urethane

Dennis,
the Urethanes I am talking about are catalyzed, there is a complete posting of this somewhere that just took place recently. I recomend full on respirators, and protection.
the Lustercote clear does crosslink to some extent, but it is not nearly as durable or chemically resistant, I would not vouch for the ability to polish them either. Just dont know much more than that.

it is kind of like comparing epoxy to aliphatic resin,, you can crosslink the aliphatic resin with heat,, but its not as strong as the two part product, is it strong enough, well lots of people use it, so it must be ok in some cases.
for me, I like the two part clears, they are generally clearer, tougher, and shine better

Dennis, I went back and found the other thread that talked about the pros and cons of two part clear and health issues, however be advised there is some dissention on the finer points, take what you will from it, its all there
http://stunthanger.com/smf/index.php?topic=11159.0