Re Honduran cages: I have some cages with floor space 36x12, and that is perfect IMO for an adult Honduran. Not saying you need 36x12 cages, but the 430 sq in of floorspace is plenty without being too large. As Chris said, most people use sweater boxes with roughly 280 sq in of floorspace, and they have success. 4ft cages are too big IMO for any Honduran. A Vision 221 or 211 can work for you.
Re Black milk cages: My opinion is to not have less than 400 sq in of floorspace for adult black milks. I've seen a 6ft black milk in a 36x24 cage, and that was way more than enough room. The Vision 221 (28x24) would be fine too. I think 4ft caging for black milks is overkill, unless maybe 4ft x12in deep.
Don't know what you are leaning towards, but here are some suggestions in case you're interested:
a) Vision 221s are versatile cages, will stack and fit your animals.
b) www.herpcages.com sizes 36x12x12 back-vent will stack nicely and are easy to heat (easier than Vision to heat)
c) www.precisioncaging.com makes a 24x20x13h model that is great for Hondurans, and a 36x20dx13h cage that would fit huge black milks with plenty of room to spare.
d) www.nsreptiles.com has racks that use Sterilite 32qt boxes. Good for Honos and fine for Black milks unless they get really big.
e) Jason's Jungle has nice racks too.
f) Melamine caging by ??? I forgot - see the classifieds - they do kits and multi-units for really good prices - I just forgot their name at the moment (is it Cages by Design?) - I think they are hosted by Exotics by Nature or someone. What is happening to me... ahhhh..