Why are you opposed to renting? Do you think that all the great directors own all the gear they use on their films? Most professional DPs/Cinematographers do not own their own cameras. "Hollywood" rents everything. That way they can always have the latest, greatest toys - or the best of the old favorites - whenever they want them.
Besides, it's not just the camera, its the glass; and most rentals companies will offer a very nice selection of top-grade lenses - much better than what you could afford, especially after you've blown your budget on the camera.
Do you have a DP attached yet? Why not let him/her decide which camera to use? Do you tell your plumber or auto mechanic which tools to use? No; you tell them what needs to be done and they choose the tools they prefer to do the job properly.
And, of course, what about audio? Have you even thought about it? A really nice entry level professional audio kit can set you back $4k to $5k. Oh, and who is going to run the audio? Same as above; you hire the sound person/team and let them use the gear that they feel will do the best job in the given situational circumstances. And what about everything else you will need - lights and electric, wardrobe, H/MU, etc., etc., etc. Have you even thought through a practical shooting budget? How much are you paying your actors and crew? What about the cost of permits and other legal papers? What about editing and audio post? How about marketing and your plans for distribution?
A piece of advice I've taken to heart - if you are not going to use it every day you shouldn't own it. After your 13 weeks of shooting what's going to happen to your camera? It will sit in a closet collecting dust and becoming more obsolete by the day. In a year you will be lucky to get 40¢ on the dollar. In two years if you get 25¢ on the dollar you've made a good sale. In five years it will be a paperweight.
The common thought seems to be "if I don't buy it I have nothing in the end." But, in the end, you have a film; or, in your case, a series of films. And isn't that why you're going through all this in the first place?