I agree with the Gracos mentioned. The Headwise/My Size/Fit4Me/Size4Me, Contender, Milestone, and 4Ever are among the tallest seats rear facing (they're all the same height rear facing).
Don't forget the seatbelt is a perfectly acceptable way to install a seat, same as LATCH, so if you'd like to install in the middle of your husband's truck you can easily do that.
Also, there's a LATCH weight limit that will be on the stickers of whatever seat you buy. For the Gracos it's 42 pounds. You'll switch from a lower anchor and top tether install then to a seatbelt and top tether install.
Wendy