Not a chance. Symmonds already tried. Look at the Monaco 2013 1500m, both Centro and Symmonds were in that race, won by Kiprop in 3:27 and second place to Mo Farah in 3:28 to break Steve Cram's British 1500 record. Symmonds was way in the back, finished around third from last. Leo was also in that race. Great race. The 1500 is a whole different ball game than the 800. Tough enough for an 800 specialist to get through rounds in a major championship in the 800; three rounds of 1500s for an 800 man? forget it, though Seb Coe did it.
The video is here:
http://www.youtube.com/watch?v=65L2pQOekRA
Amazing race by Mo, he could likely move down to the 800 and run at a high level.
Kiprop ran a great 800 in 1:43.35 in Paris this year (2014,) beating Nigel Amos, check out the video: