I have to discount the respray as that was a flight of fancy, and to be honest the stupidly sized wheels and tyres with the Gregster touch, and buying my truck in the first place as it was a gift from my mother who was convinced Banshee was worthless and due imminant death (stupid stupid old mare

)
Being honest though I reckon the following costs are realistic.
Good clean truck with tax and ticket - £500
Suspension lift:
Coiler: 2" springs - £80
Leafer: 2" lift Shackles - £50 (I have a set in my garage, and material to make more)
2" Body Lift - £50
31x10.5" R15 Wheels and tyres - £100-£200 (depending on your luck and patience on Eblag)
Other than this the rest is just throwing spanners about at a spanner party (usually held at mine for the East Anglian Possey)
Random sundries like replacing tools, nuts and bolts, spares, pipework for raised air intake etc - £100
All in at worst your looking at around £1000 from empty driveway to well prepared truck that will still be comfy enough to use as a daily drive. Obviously you don't need to find all this up front and it can be done in stages. Some of it may not be necessary, for example the body lift is a nice touch to give your toy that big and meaty feeling, but not overly useful as you will only need the extra room under the arches when going quite extreme and need the most articulation you can get.
Hope this helps.