Thank you for re-affirming my suspicion that an OTA put you in this position.
Rumrunner wasn't ever going to help you in your situation. Rumrunner is purely for achieving S-OFF. Since you're still S-OFF, it didn't have anything to do with your phone. Your root access is gone because the OTA wiped it out. It's important to always be careful about OTA updates because OTA updates assume that you NEVER modified your phone and will write whatever they want to wherever they want.
Since you can at least get to the bootloader, your phone can be saved. You said that you tried to update your SDK so that you could have the fastboot files available. When you run the SDK updater (I assume you're on Windows) you have to right-click and run as Administrator to make it work.
The files you want for fastboot are hiding in c:\program files (x86)\Android\android-sdk\platform-tools\
Take adb.exe, fastboot.exe, adbwinapi.dll, and adbwinusbapi.dll and copy them to a separate folder. (Such as C:\adb\) Navigate to that folder and do shift+right-click in a blank area of the folder so you can run a command prompt. You will want to put a ROM and a recovery file in this same folder too. (You sound like you want the stock ROM
Use the command 'fastboot devices' to see if the phone shows up. If the phone doesn't show up, then you need to go to the HTC Website so you can install HTC Sync, then remove Sync (while leaving the drivers behind) so that your phone has the correct drivers to make it show up in fastboot.
If 'fastboot devices' ends up revealing a device, then you can grab a custom recovery image file and do "fastboot flash recovery filename.img" to put a custom recovery in your phone. Then within the custom recovery you can do adb sideload romname.zip to install a ROM and that should put your phone back into a usable state.