EDITTED WITH SCREENSHOTS
For your faction only, of course. No getting destro gear as order and vice versa
This method is a bit old school involving tsearch, a fancy memory editor. I don't have any other program to do this kind of work, but am open to other suggestions. Googling "tsearch download" will give you plenty of options to grab it. Any version is fine as 99% of the versions on the web are 5+ years old and work (1.6, 1.6b, etc). It comes with a help file that explains what various buttons do. Open tsearch, start WAR, then in tsearch open the WAR process. Now we can begin searching for values.
URL with brief explanation of tsearch - Imageshack - war1o
step 1 - if influence is 0, get some influence in a PQ/RvR area. if your influence is not 0, tsearch for influence value as exact match against 4 bytes. example, you have 100 influence in the high elf chapter 1 PQ. search for "100" as a 4 byte value. you will usually get 100's or 1000000's results. don't worry.
URL for screenshot of influence - Imageshack - war2p
URL for screenshot of tsearch search for 100 - Imageshack - war3b
step 2 - get another batch of influence. kill a mob, gather a item, whatever. do a followup tsearch for new influence value. the search next icon is next to the init search icon. be sure you use search next and not init search. you want to find the new value from amongst the old ones.
URL for screenshot of tsearch follow-up search for 200 (the new influence I got) - Imageshack - war4j
step 3 - repeat step 2 until you get 1 result. this is your client-side influence value. double click the line in the search to place it in the results tab.
step 4 - enable autohack debugger from the authohack menu (if already enabled, it is greyed out). DO NOT FREEZE THE LINE IN THE RESULTS. instead, right-click and select autohack from the popup menu.
URL for autohack step - Imageshack - war5qhd
step 5 - get more influence via mob kill, item gather, just standing there in a group, however. from the authohack menu, select the autohack window. in the autohack window, it has the mov[eax+0x8],edi instruction (or something similar) in the top. this signifies the instruction that getting influence executed in memory. on the disassembler tab at the bottom of the autohack window, right click the first line (mov [eax+0x8],edi) and select "register."
URL of autohack window with disassembler tab, line value, and register selection - Imageshack - war6
step 6 - in the register tab of the autohack window, use the red smily face on the BOTTOM checkbox (not the line in the top). in the Register dropdown, select EDI because mov[eax+0x8],edi is placing the value of [eax+0x8] in the EDI register. THEN in the Replace By box, select the influence you want in HEX (ie, 3000 decimal is BB8 in hex). you can get the hex value with windows calculator in scientific mode. simply type in the decimal, then click the Hex radiobutton to get the hex value. PLEASE NOTE YOU SHOULD DO THE EDI DROPDOWN BEFORE TYPING IN THE REGISTER VALUE AS IT WILL TRY TO PUT THE VALUE INTO THE EAX REGISTER (or whatever the top item in the dropdown is) AUTOMATICALLY. So change the dropdown first. Sorry for trouble folks had with this otherwise!
URL for register tab with EDI dropdown + hez value (and smily face) - Imageshack - war7s (note that FA1 is 4001 in hex)
step 7 - get more influence via mob kill, whatever. you will jump up to whatever the decimal value you put in and you should see the influence bar fill up. go back to the rally master and select your influence reward.
URL for screenshot of maxxed influence after next kill - Imageshack - war8
URL for screenshot of selecting inf reward - Imageshack - war9
Two things are awesome about this. One, if you keep the autohack enabled, you can go to any chapter pq and the system will be tricked into giving you the influence that you input at step 6. No need to kill or do anything. And two, this is client-side and has been ingame since beta. Yes, for over a year now this has not been fixed. It likely will not be fixed because it's client-side manipulation. I say client-side because if you exit the game and log back in, you will lose all the influence you tricked the system into giving you. You can keep and use the influence rewards, but you will not have any of the influence. No big deal.
It sounds like a lot of work, but really once you get used to it, 5 minutes of effort compared to doing tons of PQs and RvR for influence rewards. Not worth it. And wearing blue influence items/rewards makes leveling much easier.
No doubt someone can make this process programmatically easier. I'm a bit of a dev, but not one who can code at such low level (I'm not a C/C++ fan... damn memory management and pointers). With guidance I could figure some stuff out, though, should someone want to make this an automagic thing.
Good luck!