try broesel crosshair switcher
https://code.google.com/p/broesels-crosshair-switcher/

I have but I dont like it simply because if you're wearing the gunboats scrolling down doesnt switch weapons on the first cycle. Say if i had slot 1 with viewmodel 1 and slot 2 viewmodel 0. Scrolling down would just turn slot 1 viewmodel off until i scroll down again.

try this:
alias slot_1 "slot1; r_drawviewmodel 0"
alias slot_2 "slot2; r_drawviewmodel 0"
alias slot_3 "slot3; r_drawviewmodel 1"
r_drawviewmodel 0
alias up1 "slot1; r_drawviewmodel 0; bind MWHEELUP up2; bind MWHEELDOWN down1"
alias up2 "slot2; r_drawviewmodel 0; bind MWHEELUP up1; bind MWHEELDOWN down2"
alias down1 "slot2; r_drawviewmodel 0; bind MWHEELDOWN down2; bind MWHEELUP up1"
alias down2 "slot1; r_drawviewmodel 0; bind MWHEELDOWN down1; bind MWHEELUP up2"
bind "MWHEELUP" up2
bind MWHEELDOWN down1
bind "1" "up1"
bind "2" "up2"
bind "3" "slot3; r_drawviewmodel 1"

i dot think it'll work with melee though

Ninjad

you would have that the way you want to do it too, no way around it automatically

I'm using this one.

This has been working for me so far.

http://teamfortress.tv/thread/14560/alias-based-lastinv

i'd recommend to create your own, to get it exactly how you like it.

-snip-

There's no way for a script to know what weapon you have out or equipped. So if you use the gunboats, the script cannot possibly know to switch to slot3 instead of slot2.

If you like the mouse wheel, consider this setup.
bind mwheelup slot1
bind mwheeldown slot2
bind mouse3 slot3

This is a lot better. there's no ambiguity, and if you accidentally scroll twice it doesn't matter at all. Not only is it a superior setup, but it works very well with any sort of script you might want to do.

smobo's mentioned option is great in my opinion.
personally i use different configs for different loadouts, which has always worked great for me.

example: bind keys 7 through 0 to equipping loadout A-D + executing a script that supports that loadout.
in my case, when i select soldier, my 9 key becomes equipping loadout C (gunboats, RL, equalizer) and it executes soldierC.cfg.
in your case, you could do the same, and then just add a small script to soldierC.cfg (or whatever) that skips selecting slot2 with the mwheel, so your mwheel will then scroll only through slot1 and slot3.

for example, this is in my soldier.cfg:

bind 7 "exec soldier
bind 8 "load_itempreset 1;exec soldierB
bind 9 "load_itempreset 2;exec soldierC
bind 0 "load_itempreset 3;exec soldierD

(load_itempreset 0 is in soldier.cfg)

so if i select soldier, and then press 9 when in spawn, i will respawn with loadout C + execute soldierC.cfg. easy as that!