Hi coronadrvr, Welcome to CPF.
This should be plenty to get you where you need to be.
The driver in the light he is talking about is a D2Flex, but these are no longer made. Any way a mod that drives the LEDs that far over spec would not be a good one for a first build, its maker is a long time member with a pretty good set of skills a lot of patience and a few tools.
I agree that beating the yard sweeper is not on the table, but getting a light that makes your hands tremble when you turn it on is doable with the parts he already has plus $100.
If I was in your position I would build a tripple. Using 3 P7s you could go direct drive, or you can use 3 of the XMLs if you regulate it ( the current may be too high with XML if not)
In either case you would have a light that output between 1500 and 2000+ lumens. Just so you have an idea a standard maglite outputs like 60 lumens or so I think.
Getting a heat sink will be the first challenge you would need to over come. What kind of tools do you have to work with?
Other than that your parts list is pretty simple. Some reflectors and a driver if you want multilevel brightness. A quality lens, and some PVC pipe for a sleeve.
I'm am not going to go into a long shpeel until you decide more precisely what you want, but once you thing you have it pinned down I can give a parts list and some instructions if you want.