You need to abandon paint and use something that will let you draw the guitar full size and accuratly, maybe a piece of paper and a pencil i use lining paper for walls to draw my plans on because it comes on big rolls and is easy to get.
I like the general idea for the guitar but it wont look like that because the proportions are not correct. heres how i start to plan my guitars:
1. draw a centre line, usually about 40" long.
2. mark the nut location about 7-8" from one end of the line to allow for headstock.
3. From the nut location measure your scale length to see where the bridge will be (25.5" = fender, 25" = PRS, 24.75" = Gibson (general guide only))
4. Decide how may frets you want and find the measurement from the nut to the end of the fretboard (you can measure another guitar for a general guide or use a program like wFret for accuracy)
5. Decide on the width of the neck at the nut and mark that on (around 42mm is a good start)
6. Decide on the width of the neck at the end of fretboard and mark that on (around 56mm is a good start)
7. Join up the edges of the fretboard
8. If you have the bridge or pickups you can draw them on now, if not allow room for them.
At this stage you should at least have the fretboard and bridge position accuratly drawn, you can then go crazy on drawing the shape of the body and headstock
The main reason i posted this is because your fretboard has no taper from nut to bridge and there seems to be too much room between the fretboard and bridge. You will find that your design may look completely different when you have these drawn accuratly. Your design has a lot of parallel lines that wont be there in a real guitar, like the headstock shape and neck support that follow both edges of the fretboard.
I think this guitar could work well and i like your initial ideas.