I'm not far enough along in my brewing career to start suggesting subs. for belgian crystal grains. Yer' in freaking Denver man! Colorado is the american homebrewing capital!
Sorry. Vienna is a lighly kilned munich malt, so .75 lbs. of caramunich would maybe be a good sub. Maybe .5 lbs. vienna and .5 lbs. belgian crystal 20.
I've been fortunate enough to always have the caravienne at the LHBS when I'm there. Today they were out of white wheat AND 2-row(1 lb'ers)! I used regular malted wheat and 6-row. First time deviating from recipe on the fourth batch I've made of this. I still think that the combo. of the hops and the caravienne give the "candied citrus" hop profile that makes this so delicious, but I haven't messed with it yet to find out different. Let me know how it comes out!
I'm about half-way through the mini-mash now