I'm still getting caught up on the extra expense of dealing with 4x5 (and have yet to produce my first successful negatives, let alone a print... grrr). I'm betting you're probably right, and as such I should probably limit my chance of exposure to such temptation until my checkbook is ready for the expense of jumping to yet another format.
Makes me wish I lived in N.C. I would have you up and running in about a day. It's all about controlling process. Understanding handling film, metering, development, printing. 4x5 is no more expensive than 135. You shoot less, you get more. You stop being a picture taker and you become a PHOTOGRAPHER.