Failover clustering: tempdb on SAN?
Solution 1:
Your only option is to put TempDB on a shared disk resource, meaning the SAN. Standard disk I/O contention is what you're concerned about, moreso for TempDB since it's a central bottleneck for the entire instance.
As for how many files for TempDB, see Paul Randal's post on this subject. He's responsible for the storage engine, so he is THE expert on the subject: http://www.sqlskills.com/BLOGS/PAUL/post/A-SQL-Server-DBA-myth-a-day-(1230)-tempdb-should-always-have-one-data-file-per-processor-core.aspx