not sure why terrabytes are a cause for concern per se - one microfilm of say 600images at a useable resolution = approx 5GByte - work out just how much is required to hold the two drawers of parish registers (about 1TByte) then all the wills etc - then add in the digitised images + the newspapers (many of which are already accessible off Island to those whose libraries have signed up to the British Library newspaper scheme) + the much larger amount due to the films (many TT films I think).
The key problem is the indexing of the material + the server capacity which it seems is to include wifi (IMO a security hazard due to ease of spoofing a controller - not for the actual iCentre database but for any personal computer)