First off, forget high level spells, look at your low level spells. If you paced both classes evenly, you could concievably be seventh level before seeing your first second level spell. You would be increasing the rate at which you gain new spell levels by 50% after that over a staight class. I'm not saying it couldn't work, but it would be a labor of love. Or hate.
The feats are neat. You might also write up a PrC similar to the True Necromnancer. Frankly, I think the class is not extremley attractive, and a straight Cleric would have an overall advantage. However, it does have a few good points. A similar route could make a Wizard/Sorcerer very viable.
If you do go with fairly even levels, you are gonig to best serve your party by having your "Buff" spells in Sorcerer, and getting ever last spell you can into your Wizards spell book. With low DC's and spell penetration, you will want a lot of spells that don't deal with unwilling subjects. Protective spells, spells that target items, or opponents with poor saves, such as undead or animals. Put all of the spells you will nedd lots of in Sorcerer, and go for versatility in the Wizard classes, since you can rememorize those spells. In the end, it will be what you can do for your allies, and how you control the battle field. Obscuring mist for cover, Mirror Image to take extra hits, grease, ect. I'd also recomend getting Extend spell as soon as possible, to make the most out of your Buffs.