Are there two questions here? One is a good controller to use; the other is how many PCI-E lanes that controller should have?
You can go from the simple and inexpensive (some motherboards will do Raid0 using the CPU) to the fabulously expensive, such as this: http://www.adaptec.com/en-us/products/controllers/hardware/ssd-caching/performance/sas-5805q/
for about $1,215 plus tax. What processor / motherboard / os are you using? Are you planning to boot from this fragile Raid0 monster, or use it for data? How good are your backup plans?