So, a new hotkey mod that allow you to bind 2 or more spell/gears to the same number hotkey already present in Vanilla Oblivion.
Example: You press hotkey NUM1 and there I assigned the two Command spell I have. When you have selected the NUM1 key, you can scroll between the spells (using the mouse scroller) assigned to that hotkey.

I am no modder, so just use this if you want to.
BTW, if there are mods like this please send me a link

PS: I have used one of the hotkey mods which lets you assign all spell/gears to the scrolling mouse. That didn′t really work out for me.

http://www.tesnexus.com/downloads/file.php?id=34735 gives you something close to this. Including Cylcers (can scroll through a number of items/spells on one key) and Mult-casting (using more than one spell in unison, with the single press of a key.)

ANB Item Switchers already does that. You can assign 4 items to a hotkey (spells, weapons, armor, torches, etc) and pressing the hotkey will allow you to scroll through them.

Just use Enhanced Hotkeys and you won't have to worry about scrolling through spells on a single key. It gives you 40 keys at a time with 3 modifiers, for a total of 160 keys, so you'll have plenty of room for binding all your spells. Plus you can bind two to a key and cast them both at the same time, or at least back to back. It also includes gear key options and allows any key to be used for objects as well as spells. It's the only hotkey mod you're going to need with this game.

Improved Hotkeys already has these features. The Mod Idea is pointless because there already exists one