OxygenBasic's Public Domain engine would be Candidate #1 to re-create a 100% keyword-for-keyword replica of 32-bit only and Windows only PowerBASIC from scratch. Currently, O2 has only rudimentary BASIC-specific vocabulary of its own, happily swallows nearly 100% of raw NASM input, supports perhaps 70% of genuine ANSI C preprocessing verbatim, generates solid 32-bit machine code, and is already capable of generating (still buggy at times) true 64-bit output. And it is entirely devoid of any licensing issues (and anarchy!) you may encounter trying to move along the GNU GPL trends or using e.g. rock-solid MASM or VC as your development platform. The only challenge would be to move the O2 engine itself away from its current FreeBASIC implementation and port it to a decent and predictable ANSI C compiler platform like GCC or similar, which would also open up a truly multi-platform perspective before the projected PB "successor" (or "replacement", if you will).
And it would also be a perfectly legal alternative to otherwise wasting one's money and effort on a known-indebted PB Inc. affair.