Hi,
It sounds like you just need a free running XO so that you can focus on performance. I have had really good luck with the Crystek CCHD-950 in the past. This part is similar to the VCXOs that we often use on our evaluation boards but are fixed frequency. I believe the CCHD-957 is even higher performing.
http://www.crystek.com/home/oscillator/clockdetail.aspx?pn=CCHD-957
Either way I think Crystek is a good starting point for these high performance fixed frequency oscillators.
Regards,
Kyle