Paul - the IomFHs publishes MI's, Burials and a transcript (somewhat erroneous + garbled in sections) of the 1851 census - all these are on paper - I had long, tedious and totally unfruitful discussions that they should think about publishing these on CD Rom to avoid the high paper and postage costs - the profits from the sales are reasonable but relies on free labour by a few members - if you put these on line then you need to consider any loss of income - if you place in a members only section then this needs to be secure.
Brian did a will index and linked this to donated transcripts - he gave the society this (+ his indices to burials, census etc) - I presume they can be maintained tho judging from the wills this does not appear to be happening.
There are indices to the presentments currently underway by volunteers (all members) from the Museum Microfilms - suggest these.
There was an index to BMDs in newspapers 1850-1865 (extending that upto to 1850 done in the 1960's) - again on card on Museum.

There was talk of an index to the journal to extend that done by myself - I had offered to do this in return for putting on a few more years of journals but was very strongly rebuffed.

The gedcom files can be updated - there are many trees submitted to the library of varying accuracy - I'm not sure how these can be added without a vast amount of work other than using pdf images

Property Records are a blank area as far as Society publications are concerned.

There are many other misc documents (eg 19thC School rolls) that can be transcribed.

I hope you have more success than I did in moving this forward.