I want to upgrade my 1/10 4WD buggy to brushless, but constricted on space due to the chassis. Any recommendations on an brushless 60A minimum ESC that's no bigger than 26 mm high, 48 mm wide and 50 mm deep?

Small ESCs that come to mind are:

R1 LCG
HW XR10 Pro Stock
Tekin RS ECSs

The dimensions you specified are pretty big except the height.

Thanks, these meet the dimensions criteria, but I notice the recommended models are spec'd for 2S max lipos and 2 pole motors - my motors are mostly 4 pole and I'd like to run 3S lipos from time to time. Any models out there that does 3S, 4 pole and is 28 mm absolute max height (with or without heatsink/fan)?

It is just slightly over size(length), but our Mamba X is designed to run any sensored or sensorless motor with any pole count on up to 6s(depending on the max rating of the motor) without issue.

Length: 2.14" (54.4mm)
Width: 1.39" (35.2mm)
Height: 1.18" (30.0mm)
I just measured one to be 20.11mm without the fan. A 1/10 4wd buggy should be no problem and the fan should not be needed.