The ball is in my court!
I play breton vampire spellswords.
Here is my build at level 48 (master level)
http://skyrimcalculator.com/#99047
This is the end of the build : http://skyrimcalculator.com/#99050
(I am on PC so I have balanced destruction and multiple runes and extra spells and ect ect ect. YMMV if you are on a console)
As said above, you will want to pick up necromage.
Get light armor- the windwalker perk will keep your stamina regenning even in the daytime
Get the regen perks in restoration - they will keep your magica regenning even in the daytime
Since you are going illusion, you can skip the ENTIRE left side of the sneak tree since illusion spells (muffle and invisibility) are superior to those perks. You can save a whopping 5 perks in this way.
Don't forget the vamp 25% to illusion, you may want to branch that entire tree because of the buff you get to the effectiveness.Or you could just kill everything (as I do) and just use illusion for silent casting and muffle+invisibility.
Get the Atronach perk at the top of alteration, its effect is compounded by vampire necromage. That combined with the atronach stone will make you immune to magic.
Being a vampire meshes well with the major skills you mentioned. It will be a very fun build. Getting invisibility as a spell makes even being a level 4 vampire a trivial matter, since you can just disappear at will.
No one makes a sharper sword than a necro-vampire.
Weapon recommendations: dagger/sword bow + spells for range.
Pick up paralysis when you are up there on the alteration tree. ++ you do not need to put multiple perks in armor effectiveness since you will have ebonyskin for cheap (to help put you over the cap.) - oh, and ebony armor will be 25% more effective and 50% more duration thanks to necromage, just like all your self effect spells.
Once you are casting invisibility/calm/frenzy/paralysis/detectlife/detectdeath/runes/shockspells/armorskin/soultraps you may find yourself becoming a vampire spellsword.
