I've been looking into building a MAME cabinet as well as some custom arcade controllers recentyl, and I was wondering if anyone knew of any stores/sites with good deals on joysticks and pushbuttons.
ultimarc.com - AWESOME customer service and great prices
happcontrols.com - has everything but it can be quite expensive
mamemarquees.com - does a nice job on artwork
arcadedepot.com - will build something custom for you - good customer service too
arcadeshop.com - also has a lot of original parts for sale and they are great too
If you really are building a MAME cab go to arcadecontrols.com - everything you need to know is there including links to parts vendors and an extremely helpful message board plus hundreds of examples with pictures and everything. Have fun - I love it.