I have never seen an aftermarket rod for the 250, however it seems like there should be one.
My Husky 1994 360 con rod went after 6 years (shortly after I started using Redline Racing oil). I replaced the rod and was still using Redline Racing oil. The rod failed agian in short order, probably due to corrosion. I then replaced the crank and have had no problems for about a year now using MX2t oil.
The rod kit was $220, the crank was $300. The time effort to change the rod is worth paying the extra 80 bucks for a new crank! Heck, some shops are now charging $125 just to change the rod.
If you choose to change the rod, make sure to set the rod big end side clearance at the LOOSE end of the specs. Not doing this will reduce the life of the big end bearing.
Chris