I don't know if someone may need it or sth else exits. But I won't read the complete 237 paged thread. 
I have written a !buylevel plugin. And after 3 days testing I think threre are no more bugs.
Players can skip current level by buying the next level.
Version 1.2 (updated 02-20-2013):
User commands:
"sm_buylevel" in console
"!buylevel" or "!sm_buylevel" in chat
"/buylevel" or "/sm_buylevel" in chat for silent trigger
CVARS:(with defaults)
If you load the plugin the first time, a config file (gungame_buylevel.cfg) will be generated in the cfg/sourmod folder.
sm_ggbuylevel_enable "1" -> Enables/Disables SM GunGame Buylevel.
sm_ggbuylevel_announce "1" -> Announce how to use buylevel.
sm_ggbuylevel_block_skip "hegrenade,knife" -> Block these weapons from being skipped with buylevel. The last level will always be blocked from skipping.
sm_ggbuylevel_cost "12000" -> The amount required to buy a level.
sm_ggbuylevel_kill_reward "800" -> The amount earned per kill.
sm_ggbuylevel_levelup_reward "800" -> The amount earned per levelup.
Changelog:
v1.2 (02-20-2013)
** CSGO support
** fixed: gg_buylevel.sp(162) : error 025: function heading differs from prototype (GG_OnClientDeath)
** fixed: bug in first round after warmup
++ added: use mp_maxmoney if available
v1.1 (01-13-2011)
**fixed: use of mp_startmoney
v1.0 (01-08-2011)
++ added: buylevel.phrases.txt
++ added: kill reward no longer give during warmup
** fixed: Native "GetConVarInt" reported: Invalid convar handle 0 (error 4)
v0.7 (01-07-2011)
** Initial Release!
Installation:
Copy the attached gg_buylevel.smx to your addons/sourcemod/plugins folder.
Copy the buylevel.phrases.txt to your addons/sourcemod/translations folder
Load the Plugin and edit the gungame_buylevel.cfg to your likings.
as a friendly reminder
money in scoreboard
THE PLUGIN WILL NOT COMPILE ON THE WEB BECAUSE I INCLUDE GUNGAME. Compiled against SM v1.5.0 and GG 1.2.11.2