mounting gps where speedo goes but keeping the fuel gauge ?

[uk-visionsa50]

in theory how hard would it be to mount a waterproof gps case like this http://www.ebay.co.uk/itm/Waterproof-GP ... 35bffd9162 around where the speedo is, but without it covering the fuel gauge and the little lights? main reason for asking is, my speedos broke and the gps i have tells me my speed, also with doing alot of exploring of little roads on the scooter i seem to get lost alot. so itd be handy to be able to have the satnav and being able to see my speed so i dont gets in trouble for speeding.........................................................................again would i be able to mount it to the handlebars without cutting too much away of the plastics and it not interfeering with the indicators and light switches etc?

[redvisionmonster]

what about a suction mount? that way you can attach the suction cup to where the speedo is, or you could remove the plastic mount on the back of the case and velcro it to where your speedo is, would need alot of velcro though, that way you wont have to cut any panels or anything.........
youll probably need a power source for your satnav too, considered wiring in a 12v socket yet ? theres some on ebay, wire straight to battery, get a fused one though, you could probably run one so itll be in the front glovebox. got me thinking now, might try this on my 89 hmmm