Spinning rod on a Flyrod blank

Rule of thumb for fly rods is 1 number in line weight for every 1/16 oz of
max. lure weight, ie 1/4 oz max weight used on lures, a 4 weight blank.
Shortening any blank at either end will slow it's action, almost all fly
blanks are already slower than casting and spinning blanks. A nice,but
inexpensive blank to look at would be the Tiger Eye Series. Platte River
Rods would be a good source, around $25 to 30 a blank, you could make it
multi-piece to store easier.
Good luck on the rod.