That doesn't sound like a good idea to me. The scalp is too oily and any make up is likely to run, especially in the summer when you sweat.
One thing you may want to consider is one of those high tech spray-on suntans. They're supposed to be really good. They even stay on through showers. I think they last about 10 days. I have no idea how much they cost. Some dermatologists offer this service. Usually an esthetician will apply it.
Of course you can always opt for a real suntan. Some head shaving web sites recommend not getting any sun on your head, always using an SPF30 sunblock when out in the sun. I would have to disagree with that. While the scalp does burn more easily than other areas, you can still tan. You just have to start slowly and be careful. Start with SPF15 use it for 2 weeks, then SPF8 for 2 weeks, then SPF4. You can start with SPF8 if you carefully limit your time in the sun. Start out with 10 minutes, then go to 15, etc. The idea is to find your tolerance for the sun, how long you can stay out without burning. I am assuming of course that you have a skin type that can tan.
Other than that, I would use a Mach3 (Turbo or M3) and shave as close as you can. Use a good shave gel like Aveeno Positively Smooth. For even better results use it along with Moore Unique Hydroglide shaving Solution. You can find it at www.mooreunique.com.
The closer the shave, the longer it takes for the 5:00 shadow to appear.