There are a number of decal making systems for both laser and inkjet printers; I don't think you can do white with the laser. In any case you'd need a color laser printer, if you are just starting from scratch then the inkjet printers are much more affordable. The only way to do white decals is to use a very expensive Alps inkjet printer (now OOP, look on Ebay) or to print on white decal paper and cut out the decals to the correct (white edged) border.
I make all of my own decals, including some pretty complex designs, for my RC models and rockets. The attached photo is of one of the vertical fins of my 1/6 scale F/A-18C turbine jet ... the devil image was scanned off a hi-res photo of the actual Hornet (here at MCAS Miramar), photo-shopped to clean it up, then printed on clear decal stock using an Epson R200 printer. I've also attached a pic of a typical rocket decal page (as used on my PML Explorer), here being clear-coated before cutting them out.
A commercial decal house wanted over $300 for just this one decal...for that I bought a scanner, printer, and enough decal stock and ink to last me the last 3 years.
Try it, you'll like it!