I believe Hilliard of Montana and Felton of Furman were the only two I-AA backs invited to the Combine (but I didn't check the status of a couple schools so may not be right on that). There were 39 backs on the list I looked at, of which 6 were listed as fullbacks. Hilliard is listed as a running back and Felton as a fullback. There was a D-II back invited too.

Hilliard measured 5'11" and 1/8, 231, and Felton 5'11" and 5/8, 241. Hilliard was the heaviest back, excluding the fullbacks. The below stats have Hilliard first

40 times: 4.63 and 4.75

Bench reps: Hilliard didn't lift due to continuing recovery from shoulder surgery right after the season; Felton 30 (tied for best and well ahead of most others)

Vertical: 32 and 32.5. This was above the middle of the pack and the two best of the heavier backs.

20-yard shuttle: 4.2 (3rd best of backs). Felton didn't do this drill, nor did many of the backs.

Long jump (standing): 10.2. Felton didn't do this drill, nor did many of the backs.

Hilliard was invited to interviews with 22 of the teams, and received good attention. Hilliard has not been able to run much in the offseason, due to his shoulder surgery. He was only able to bike for a month or so.

If I missed another I-AA back, my apologies.