I'm trying to develope a new head design that wont have any rpm limit.  I would like to use an existing long block to lower costs but I'm not sure which would be best. I'm leaning towards a four cylinder HONDA because parts are cheap and available.  This would become the prototype engine with a lot of custom work so any engine would actually be fine as long as the long block could survive 10k+ rpm. 

the first thing that will limit your engine rpm is the phenomena called valve float. Inertia of the relatively heavier intake valves is likely to make it difficult for the valve to return to the seat at high rpm.

If you see blue smoke coming out of F1 cars, that's probably due to the intake valve(gate valve) hitting the piston and broke into pieces.

I've worked on racing engines before, we normally used less aggrasive valve lift for the first few races just to make sure that we move cautiously to define the limit. 

there were some ferrari engines which (according to video games I've played) could rev to 14000rpm or higher without grenading.  

Perhaps what you should do is set up the engine so that the performance at higher rpm is miserable enough as to prevent further increases in engine speed.  In other words, for an unloaded engine, make sure that power output at 14000rpm (or whatever) is zero.  For a loaded engine you could probably do with a torque curve that falls off steeply above 50% of max allowable rpm.

a detail to bear in mind is that sometimes the fastest an engine turns is when it is being turned by something else (like by the transmission, when going down a hill).

While valve train dynamics may dictate engine speed capability, mean piston speed is also a factor.  I use two seat-of-the-pants limits:  10 meters per second mean piston speed for constant speed service (such as aircraft piston engines) and 25 meters per second for engines that hit peak rpm for very short durations (such as many motorsport applications).  Thus a 100 mm stroke engine should be limited to about 3000 rpm for continuous speed service and maybe about 7500 rpm for highly variable speed service.

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