Douglas A-20J - Boston IV

I would like to build a model who makes one I can order?

also did US forces fly them and if so where?

also how did it compare to the B-26?

Not sure of what scale you would be going to make your model and what varsion of the plane but:

1/72 scale ..
Revell 04278, 04345
MPM 72539, 72557, 72556, 72559, 72549, 72551, 72564
SpecialHobby 72337, 72287,
Matchbox 40110,
Airfix A04033,

1/48 scale ..
Revell 04598,
Italeri 2656, 2637,
AMT 8894, 8895, 8694

One of these kits can be found in one of the nearest local hobby shops or at the eBay. Also there should be a couple of online shops offering one of them. Just use the Google.

Douglas A-20 Havoc also known as Boston was used over the Europe, Africa, Asia , the Pacific and Mediterranean Sea.. These planes were used by the USAAF, RAF, SAAF, RAAF, RCAF, French AF and soviets as well.

Look here.. Douglas A-20 Havoc - Wikipedia