I found a couple of Chinese sites with a search for AE803LV but that's about it.
None of the big four I use list a 75.7575 MHz crystal or oscillator module.
It may be worth looking into having a module made, I've had 'special' ECL oscillator modules made in the past when a certain high performance video card had one fail, it was surprisingly cheap at around £35 for a one off IIRC.
Might it be possible to replace it with one of the tiny programmable parts from Silicon Labs?
I seem to remember they had some really cute programmable oscillators in a tiny footprint that had EEPROM to store a startup configuration, marketed as a crystal replacement and could be field programmed or supplied programmed to your choice of frequency.
I'm not sure how good the stability was though.
(Edit.)
These things, best stability is 10PPM so it may not be good enough.
http://www.digikey.com/product-search/en/crystals-and-oscillators/programmable-oscillators/852047?k=SiTime&FV=fff4000d%2Cfff8004f&stock=1