I've never found anything. I added a pillar guage pod and have trans temp there. I'm hoping to add a small tach there someday and one more thing to my third slot. It's not nearly as good or complete as a Scanguage, but better than nothing. You can get an OBD-I scanner from Ebay for around $20 if I recall correctly and it will check codes better than the count-the-light-blinks method.
IMO, the biggest disadvantage to a pre-96 vehicle of any make is the lack of OBD-II for code scanning.