www.hobbycity.com has an ignition cheap that some have been playing with.
www.ch-ignitions.com now sells the RC Excel ignition. It has auto advance and is cheaper than CH's regular ignition. I rather trust it as CH Ignitions is a quality company, and they wouldn't become dealers for the RC Excel ignition until they had tested it and requested some changes from the manufacturer.
Some of the suppliers have fallen by the wayside.
www.lambertsrc.com is still going, and I believe he will take custom orders for mufflers and prop hubs; besides what he normally has in stock.
www.wackerengines.com still has their website up, but I haven't heard from them for a while here in the forum. Either one, given that they are both in business still, offer good parts and service.
AV8TOR