In my quest to re-learn long forgotten electronics, I started looking at 555 IC timers for my circuits. 555's are great and all, but it looks like they cap out around 200KHz. I'm looking to push some pulses out at much higher rates in the 10 to 50MHz range. Does anyone have any recommendations as to where I should start looking in the way of chips?

Possibly crystal oscillators. You can get them in generic frequencies from the big componet houses. I have used these before :Thru hole oscillators :: oscillator products from International Crystal

If you need a square wave osc check out LTC1799 which does 1Khz to 33MHz or if you need higher then LTC 6904 which goes up to 67MHz

Here's a sample circuit: Electronics -- Small Footprint Square Wave Oscillator