About the wife thing: maybe that's why men flock to fundamentalist churches - because the pastors tell'm that it's the man who makes the decision in the house, damn it!
Not my piece of cake. My best suggestion would be to list/promise/make sacrifices with other purchases and count those real savings toward the purchase price.
Your problem may be deeer, though - perhaps your wife is mainly embarrassed that you'd want to draw that much attention to you.
A friend owned an Allewedder (and a garage filled with weird bikes, including the 7 person "conference bike". He always draws a crowd, some of which openly ridicule him. Know what you're getting yourself into.