all the BDM info is fully available on Mormon microfilm as indeed so I believe are most of the IoMFHSoc MI's as I know Noreen used to send them a copy - there exists several indices to other material on card index at Manx museum transcribed by volunteers - these include a much better index to episcopal wills(fuller + fewer errors) , presentments, BDM entries in Manx Press upto 1865, people named in wills as well as the card index to Manx Newspapers - putting these on line would make a huge difference.
The Mormons have suggested that they intend to put the actual microfilms online - this for the Manx material would require permission of the copyright holder (IoM Govt) - there is a suggestion that a new Manx Museum will include a family history section - if so then I would expect some digitalisation of these films + indices. There exists other full transcripts that for various reasons are not on-line (eg full census transcripts, parish records)