I'll agree with using parts bikes since you can easily harvest a good set of horizontal drop outs from an old bmx frame and if you can weld and make up a jig, this can be pretty easy, but definitely practice practice practice, then practice some more...
If you got a welder and a plasma cutter, making drop outs can be done quick and easily, but I don't know what kind of equipment you have to work with. Even a band saw will work and save you a lot of time, but anything less than that and it's better to buy them pre made or harvest them from junk bikes.
I got some plans for making a motorcycle jig which could easily be applied to making a bicycle frame as well as a LOT of plans for forks like springer, leafer, and girder type, and same thing... they can all be scaled down to be used on a bicycle, it all depends on what look you're after and how well you need it to handle, but the girder type is by far the best handling type since it doesn't change the rake and trail as the spring compresses like the telescoping type forks used on most motorcycles, the reason most motorcycles use the telescoping type is to save on production costs, and they've been really advanced by using cartridges that control rebound, compression, nose dive on braking and really tight cornering etc, they can be made to work really well.
If a solid fork is all you're looking to make, there are severall designs to choose from whether it be a BMX type like the older mountain bikes use or a tripletree design which looks great and also offers good strength, but the steering needs some stops added to prevent tank dents.
But with a proper frame jig, you can easily set up the rake and trail to make the bike ultra stable or a bit less stabile in favor of faster turning capabilities etc...
Here's a site you can read all you need to know about frames, rake and trail, and which front end will suit your needs best... If you got building skills, the right tooling, and a good understanding about setting up rake and trail you can make a killer bike that'll be perfectly stable at any speed as well as excellent handling for whatever purpose you want the bike to serve...
Read the articles and download the plans etc... there are plans for frame jigs, tube benders and notchers etc that'll help you no matter what you want to build...
http://www.chopperhandbook.com/