in which case you minght be interested in this http://www.cruisercustomizing.com/detail.cfm?model_ID=0&Category_ID=110&manufacturer_ID=141&product_ID=2257&sblid_name=Radiantz_ILLUMINATORZ____LED_License_Plate_Lights__
ooooh! Niiice
Cheers
Lights glowing is always a good thing. Pitty mines broken! 
The only way your licence plate will be “legal” is if you follow 2 guidelines:
1/ the plate must be in plain sight, visible at a 45 degrees angle, with no obstruction.
2/ the plate must be mounted at the rear of the bike or on the left side.
The note on the left side is for people on the pavement to be able to see your number plate (bobbies and gatso like…)
Those guideline are the one we use for cruisers and choppers.
What about a quick telephone call to the DVLA!!!
Please note as well that even if Harley and cruisers get away with it, it is mostly because lots of them have it done. So when the law look at it, they don’t bother.
If you do that on a R1 or Fireblade, it will stand out of the norm and ultimately, bring more attention to the motorbike in question.
If you do go ahead with the modification, 2 things you could do to make it beter:
1/ use a legal size yellow number plate.
2/ move your break light to the side.
7’s been through 2 MOTs with an unilluminated std size plate in normal position if that means owt to the discussion. It was daytime when the MOTs were done tho 