Northbeach,
Perhaps your HUD symbology could be automatically repositioned higher up the glass shortly after weight-on-wheels (ie when the attitude or velocity vector are no longer relevant)? This would avoid interference with airfield lighting. An easily-visible groundspeed readout is very useful during a rolling landing and when taxying at night. The heading tape can also be useful in reduced visibility to confirm you're taking the correct taxyway!
Some HUDs use auto-brightness sensors to adjust the symbology brightness without input from the pilot. My experience of these is somewhat mixed and it can be quite uncomfortable when the symbology incorrectly fades from view at a critical moment! A simple solution is to include a manual HUD brightness control wheel as one of the "HOTAS" switches and this is worth considering. It doesn't have to be in a 'prime' position but it is certainly handy to be able to adjust without removing hands from controls. This would also allow pilots easily to turn the brightness to zero if they didn't want the symbology on the ground.
If your tilt-rotor is to have military application then don't forget to include a countermeasures dispense button somewhere on the stick. Automatic systems are not foolproof yet! A 3-way transmit button (Com 1, Com 2, Simulcast) is useful for military flying as well; the handling pilot may need to communicate on ATC and on a formation frequency in rapid succession.