xNote: TEI also manufactured several S100 chassis similar in design to Imsais like an Imsai with no front panel and the right side had no vents:
12 slot mini-chassis.
12 slot full size chassis with MB in rear & cutouts up front for three 5.25" drives.
Disk drive cabinets:
Mini chassis with no MB but cutout for three 5.25" disk drives (often stacked with 12 slot chassis).
Dual 8" cabinet.
All TEI power-supplies used ferro-resonant power-supplies (Constant-Voltage-Transformers) which ran most S100 cards cooler than other chassis. The CVT's also ran better with poor quality line voltage.
Most TEI's were sold as empty chassis that people populated with other (better) cards. TEI started out as a power-supply manufacturer for mini-computers then decided to jump on the S100 train. The made 8080 based systems when everyone else was building Z80's. They made great chassis's but poor cards.
TEI chassis are fairly common but the entire TEI computer is very rare.