I was in the same position as the OP looking for a low business award from Philadelphia - Venice. I have been logging in almost every day for the last two months (it is a seasonal nonstop) to check availability. Usually the best I ever see are flights a day or two apart.

Yesterday I was able to find a flight departing Sunday 5/31/15 with two low business (50K) award tickets. As usual there were no low business tickets for the return but I was able to book two low coach (30K) tickets for Saturday 6/6/15 which was day 335.

Figured I would see if I could snag a couple of 50K business tickets this morning for 6/7/15. I was up during the night anyway so logged in a few times but got a message no tickets available yet. At 3AM (EST) there were only high business award tickets.

Finally I get up and log in around 6AM and to my surprise there were 50K business tickets for 6/7 and 6/6. I had to pay the $300 redeposit fee and $100 award booking fee to upgrade and change my flight to 6/7 but I was happy I was able to get the tickets I wanted for weekend flights in both directions.

As far as I can see there appears to be as many as four low business award tickets for the flights I booked. Right now I have the only business seats assignments on 5/31 and 6/7 but only the 5/31 flight currently has low business availability for two so maybe someone has a hold on two seats for 6/7.