Co-CEO Mike Lazaridis of Research in Motion announced that the previously announced 4G version of the PlayBook tablet will not arrive as scheduled this summer. RIM had previously announced both a WiMAX and LTE 4G models to show up this summer.

From what we are hearing now, the WiMax version for Sprint, the LTE version for Verizon, and the HSPA+ model for AT&T are all delayed until at least the end of August, or what RIM is referring to as early fall. This now lines up with the delay that we told you about for the BlackBerry Bold 9900/9930, also on hold until at least the end of August, the 4G PlayBooks, and the Bold 9900/9930 were all supposed to arrive this summer.

No one is speaking on the record as to the specifics of the delays, but from some of the whispers we hear it is a combination of things.  Apparently, it isn’t one specific thing; the desire to consolidate and improve the software is at least part of the equation, but the cost and availability of specific parts is also playing a role, if you believe what we are hearing.

Despite the fact that RIM has moved 500,000 BlackBerry PlayBooks in Q1 of this year, the amount of real success is questionable when compared to the challengers. Analysts that we have spoken with indicate that RIM’s inability to execute is causing it to fall behind competitors in this space, which isn’t good for the company or the company’s stock price. Since the announced Q1 earnings missed estimates and the Q2 outlook isn’t much better, rumors suggest that at least some layoffs are coming.