Unfortunately, using CoolRunner isn't an option for me as I have already commited to 9500 series CPLDs. Moreover, as laroche pointed out, CoolRunner's present/future is uncertain. However, I found the link regarding modifying the hystersis very useful. I did not know that all inputs already had 100-200mV of hystersis.
I will have to experiment once my shipment of CPLDs arrives to see if this is enough for the output my sensors yield. Otherwise, I will try to add external resistors as outlined by the document. Basically the schmitt trigger equiv is not possible in VHDL - this is what I've gathered.
Also, I looked at the link for the octal schmitt trigger - this does seem to be the largest package out there (I wasn't even able to find this, I was using the hex so far). I guess this isn't so bad, I may end up using the 20 octal schmitt trigger chips external to the CPLDs. I reckon the 20 chips will not draw too much current - anywhere from 20mA to 200mA, depending on CMOS/TTL. Inelegant but may be a simple "necessary evil" in order for me to create my prototype.
I will have my CPLDs within a week, so I shall have to test then - I'll post again to let you know how it went.
Thanks very much for your advice again, very much appreciated!!!
You guys are awesome!
Avital