Hi Fishlore:
Harrysin's suggestion of using a v-bit, free hand style may not be a bad idea at all. I've tried it several times in the past, but it's important to map out your letters first. A trick I use is a word processing program with the capability of making banners. Some are on the market for under 20 bucks and you can make an entire room banner with standard 81/2 x 11 paper. The printing stage helps with that. The program I have used is by Hallmark Cards (on website). It may be worth the bucks if you do frequent sign work. Also a great help is a product sold by MLCS of Ohio (mlcswoodworking.com). It's called the On-Point router plate. I bought one and it's great for many free-hand routing purposes. The plate is adapatable to numerous routers (plunge also) ans is a clear lexon, equipped with a laser guide light and s series of leds (to replace the duck taped flashlight method). I bought it 2 years ago for about 70 bucks, but I noticed they have it on sale for $49 with free shipping (I've used MLCS many times and their cs/return reps are great to deal with). The router plate is over-sized to give extra support and controls "tipping". The website has videos, more info and is worthy of visiting. Their toll free customer service/tech number may also be able to assist with your question (believe it or not, at no charge). These are only suggestions and I realize that everyone's on a budget, but if you're making signs often, these helpful tools may be worth looking into.
Good luck!
- Bob