4 x Nvidia GTX Titans

I am pretty sure you can

Do you have a budget?

Is the potential setup for gaming or GPU processing, or just a theoretical argument? If gaming I hope you're going 37" @ 4k x 3, which I've yet to see so post some pics.

noobs

I hope you are gaming at 1440p at least because if you go 1080p you are wasting money. What is your work?
Yes you can, blu ray drives and fan controls take up space in your 5.25' bays. Graphics cards are internal and take up PCIe slots.

Doesn't sound like a very taxing job. If you want over 9000 FPS on Battlefield (Not that your current display can show more than 60)
PCPartPicker part list: http://pcpartpicker.com/p/2aPK1
Price breakdown by merchant: http://pcpartpicker.com/p/2aPK1/by_merchant/
Benchmarks: http://pcpartpicker.com/p/2aPK1/benchmarks/

CPU: Intel Core i7-4930K 3.4GHz 6-Core Processor ($576.98 @ SuperBiiz)
CPU Cooler: Corsair H110 94.0 CFM Liquid CPU Cooler ($89.99 @ Newegg)
Thermal Compound: Arctic Cooling MX4 4g Thermal Paste ($5.99 @ Newegg)
Motherboard: Asus Rampage IV Black Edition EATX LGA2011 Motherboard ($499.99 @ Newegg)
Memory: G.Skill Ripjaws Z Series 64GB (8 x 8GB) DDR3-2400 Memory ($719.99 @ Newegg)
Storage: Samsung EVO 1TB 2.5" Solid State Disk ($549.95 @ B&H)
Storage: Seagate 4TB 3.5" 7200RPM Internal Hard Drive ($169.99 @ Amazon)
Storage: Seagate 4TB 3.5" 7200RPM Internal Hard Drive ($169.99 @ Amazon)
Video Card: EVGA GeForce GTX 780 Ti 3GB Video Card (3-Way SLI) ($699.99 @ SuperBiiz)
Video Card: EVGA GeForce GTX 780 Ti 3GB Video Card (3-Way SLI) ($699.99 @ SuperBiiz)
Video Card: EVGA GeForce GTX 780 Ti 3GB Video Card (3-Way SLI) ($699.99 @ SuperBiiz)
Sound Card: Asus Xonar Essence STX 24-bit 192 KHz Sound Card ($164.99 @ Newegg)
Case: Corsair 900D ATX Full Tower Case ($259.99 @ Newegg)
Power Supply: EVGA SuperNOVA NEX1500 Classified 1500W 80+ Gold Certified Fully-Modular ATX Power Supply ($329.99 @ NCIX US)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($14.99 @ Newegg)
Operating System: Microsoft Windows 8.1 - 64-bit - OEM (64-bit) ($99.98 @ OutletPC)
Total: $5752.78
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-11-28 22:56 EST-0500)

Keep in mind that these parts cannot be considered overkill because they are 50 miles past that. This will last you about 7 years before upgrading so I sincerely hope you don't get the AIO cooler and custom watercool your system. Tri-SLI will beat Quad-SLI, they will run very hot so again, watercool them. Windows 8.1/7 is your choice. I suggest keeping the optical drive cause they look terrible on such a nice case. Remember to buy a case fans.