Funny you should bring that up!  I am about to make one - I envision a base with 2 uprights, slotted to hold the arrow, the base would be about 8-10 inches and the uprights , maybe 4-5 inches.  I think the height would also hold the arrow for wrapping the fletching.  The base would really be determined by how long your crest is.   Not fancy by any means, but a heck of a lot cheaper than $140.00!
Hawkdancer