i really like the concept and can see why the germans really like the 48T on their trekking/expedition bikes

edit: bring it to bike shop that sells CUBE in the UK and they'll have the set up you want on the bike in house. my guess in that running a 48T is possible on an MTB frame ... but it probably requires the equipment to run at the outer edge of its operational window, therefore a CUBE dealer would be better suited to deal with it, as they use it on their touring/trekking bikes.