rigid coupling, stepper to leadscrew

Again on the subject of the KT150 table conversion:

http://www.indoor.flyer.co.uk/kt150conversion.htm

I was wondering exactly how bad an idea coupling the leadscrews (2mm
pitch 10mm diameter ACME) directly to the screws would be?

The screws are unsupported at the other end.

Obviously the motors would take end loads but they have bigger
bearings than I would use for thrust bearings even on the small ones I
have, they are also dirt cheap. Endplay is had to detect but then I'm
only pulling and pushing on them by hand.

Alteratively what is the shortest and thinnest method of adding a
bearing to the end of a screw? I'm considering two thrust bearings
and a needle roller to make the machining super simple (just one hole
for the needle roller).

Graham