You would buy the SSDs necessary to create your own flash array. But the issues here are price/performance and reliability. SSD reliability right now isn't any better than HDD and price is much higher. The day that SSD replace HDD en masse isn't coming as soon as you think. Since the purpose of deduplication technology is to reduce the amount of data you need to store and move across the wire the need to use SSD (flash) to move data even more quickly lessens.
At some point there will be an all flash DXi type system from QTM or someone else. But the price of that product will be prohibitive for quite a while.
Thank you Milehigh for your insights and lesson for me. You say quite a while before that technolgy is cost efeective compared to DSI. In your opinion are we talking a year or 5 years or something else. thanks again for your response.