I think the only realistic carrier left to operate IOM and Jersey is easyJet as part of their continued expansion...
However they have this pretty much sowed up from Gatwick, so could only imagine if they were to start the route it would be 3-4 times a week to each location.
Other than BMI Regional that has been mentioned previously, there are other regional airlines like CityJet, Links Air and City Wings...
The latter two carriers operate the 19 seater BAE Jetstream 31 into the IOM already, would the airport be interested in attracting a carrier operating this type of aircraft from Luton? Or is the airport focussing on airlines operating larger aircraft like Gatwick... From what I understand they charge a disproportionately high fee for the smaller aircraft, to keep these out and maximise the limited runway slots.