I think in just going to go with two dart tires... Still debating =)
That is a T E R R I B L E idea!
It's worth spending some time, re-reading what everyone else has posted here. Just to clarify; the DART is intended (and stamped as being) a DIRECTIONAL FRONT WHEEL TYRE - this means that it should only be put on your wheel one way round AND only on the front wheel. It is not intended or designed to be a rear wheel tyre at all.
The SMOKE is a tyre that can used on either front or rear wheel. Most people used them on the rear primarily as it had a particularly gnarly and grippy climbing profile that dug in brilliantly and much more so than most of tyres of the day for superb climbing properties, but it also cornered very well too, as well as shedding muddy crap very well.
If you want to put the same tyre on both wheels - it should be the SMOKE. If you want to put a specific directional tyre on the front, then have a go with the DART (but only on the front wheel) - you can see here that some people really like it (the DART), and others don't. However, what isn't in much doubt is that the SMOKE is a brilliant tyre that is almost universally loved, that we all wish was still in production today (especially in an amberwall finish)!
IMHO putting two DART's on both wheels would be a terrible mistake, that would be expensive to do and give you terrible handling characteristics....
There's a guy on another thread on this forum who has a bundle of brand new Smoke's that he's imported in bulk - they're about £33 each if I recall. Why not buy two of them to start off with and if you really want to, buy a DART afterwards after you've ridden them a bit from your online source in your OP and try it on the front - if it turns you don't like it, you can always re-sell the used DART on here someone will defo buy it from you.
EDIT: Reviews (Don't just take our word for it):http://www.bikeradar.com/gear/category/ ... yres-31780http://www.mtbr.com/cat/tires-and-wheel ... 51crx.aspx
Rossin Concept MTB 1990 - Full XTR M900
Litespeed Ocoee Titanium MTB 1992 - Grafton / Bullseye / Syncros / XTR
LeMond Z Team Issue SLX 1991 - Full Corsa Record / Sigma
LeMond GAN Team Issue GLX 1993 - Full Dura Ace (7400)