The Radisson is kinda fickle about their crew rates. If they have too many rooms dedicated to crews, they will not give you the rate no matter how many rooms are still available. Ask for Danny (I am not positive that he still works there) at the Laquinta and he will do you a solid. Remember, the 500 and the inevitable march madness round in town will render everything obsolete.
Note-I haven't commuted to indy for about four years, but here's what I remember.
1. Radisson (as mentioned above)
2. La Quinta - used them a lot for the free breakfast and slightly cheaper rate than Radisson
3. AmeriSuites (or some chain like that) near the airport also had a ~ $40 rate and included free breakfast on weekdays only
When I was there, some CHQ/S5/RP dudes were running a crash pad in one of the "suite" hotels, and charging like 150/mo or $20 a night if you could catch somebody while they were there (obviously sharing a room).