Michael, Paul's idea with the front group of a 12 - 14 inch Petzval is a good one. A really beautiful soft look. Another neat lens is the 11 inch Verito. Perfect for your wee cameras but take the front group away and just use the rear alone.
This portrait of John Merly was done on 14X17 with the rear group of the 11" Verito. It becomes about a 24 inch lens but of course for a portrait I was somewhere around 32 inches perhaps. Not so fast any more that way, but still very pretty.
OK, looking at this, calling Merly pretty is beyond a stretch.....
Jim's idea is a good one, but the 11 1/2" Verito converts to a 20", not a 24", when the rear cell is used alone. Should still have plenty of coverage for 11x14, but it isn't going to meet the "inexpensive" part of your criteria.
I wonder how your Artar would work if you unscrewed the cells a few turns to increase the spacing. This is essentially how some of the variable soft focus lenses work, but they're probably different formulas than what an Artar is. Still, it would cost little to find out. Just don't unscrew the cells so far that they fall out!
I'll try messing with the Artar and see what happens. Thanks for the leads so far guys.
i would say unscrew just the two elements in the rear. not the entire group but rather the elements of the rear group. could be nice.