In your case building would most likely be your best option due to your size and some of the chassis specifics that you list. The first thing that you need to buy is the relevant SFI spec so that you can make sure that the car will pass tech.
If you have access to a bender (and the skills to run it) a basic blueprint would most likely be your best option as you can adjust the dimensions to suit your size. Most kits will be a pile of straight tubing and a small collection of bends along with possibly a mid plate and maybe some tabs. In your case I would put the shoulder hoop a little higher than what will be the norm with most plans so that the roll cage does not end up too tall. Put the motor out far enough that the car will not have a tendency to wheelie--remember that your body weight is mostly behind the axle. Invest in (or borrow) a line up bar to keep the engine and rear end aligned. Search the net and find the Hot Rod Magazine story that details Don Long's construction of Ed Pink's Old Master as it has a lot of useful info that still applies some 50 years later. Mark Williams and Chassis Shop have front axles available off the shelf and shops like MW, McKinney, S & W, Chassis Shop and Neil and Parks will have all of the brackets and tabs that you need along with dragster specific components like mid plates.
If you don't have a jig or access to one you can still do it the way that Long did when he was starting out. Set the driveline up on a flat floor with the rear axle and motor where you want them and connect the dots.
One way that works well for a one-off build is to make a base out of plywood (or similar) and screw/glue blocks of wood to it to locate the lower frame rails at ride height and work up from there using a marked centerline on the wood to keep things straight. Use a pre profiled motor plate and you will have the location for the upper rails as well. Sit on a block to locate your butt at the correct height with your legs draped over the rear end and have a friend measure to establish the height of the shoulder hoop. Use a good quality level to keep everything square and use the mid plate as a datum point for longitudinal measurements. Your shoulder hoop will be wider than the lower rails (unless you have a really big arse) so put the level vertical and measure in to center the hoop. A plumb bob hung off either side of the top hoop/rail is also a good way to make sure that the upper rails are centered.
Some of this may be TMI if you already have chassis building skills but I figured that this was a good chance to give some tips to any one else who is contemplating their own build.
Roo