Try Ribas — a small rental outfit in Quito. We too ran into the absurd cost/rules. Even with damage waiver insurance from their own web booking sites, the “big boys” Avis, Budget etc still wanted several thousand on our credit card for a damage deposit– that would have covered by their own insurance. This is often said to be subject to a high hit from nearly imaginary damage from these same guys and havoc collecting any claim.
Anyway, Ribas rented us an economical but larger than sub-compact car (I too am 6′ 200#+) at about $42 a day all inclusive for a month; plus $75.00 for the month for a new gps. The did ask for a damage waiver but only swiped our card for need if it arose–they did not run a debit or hold on the card (I checked) They were careful, through, and easy to deal with. She speaks good adequate English and writes it well–responding by email promptly. Once we needed road service — they were right on top of it. No complaints, good folk. Try this email from my records: cubacar428@yahoo.com or ribasrentacar.com
Barry Laing