Taco has found the reason why \mathaccents may get dislocated in slanted or italic fonts
The problem is that your code does not set \skewchar for the \scriptfont and \scriptscriptfont of the relevant math families. You need to make sure you set all three of \textfont X, \scriptfont X and \scriptscriptfont X.
This requires some minor rewriting of a few macros in font-ini.tex. I could do that for you, but my coding style is not even remotely similar to yours so I wager you'd rather do it yourself. ;-)
font-ini needs the following patch \appendtoks \dosetmathfamily\mrfam\textface\scriptface\scriptscriptface\c!mr\mrfallback \dosetmathfamily\mifam\textface\scriptface\scriptscriptface\c!mi\empty \dosetmathfamily\syfam\textface\scriptface\scriptscriptface\c!sy\empty \dosetmathfamily\exfam\textface\textface \textface \c!ex\empty \dosetmathfamily\mafam\textface\scriptface\scriptscriptface\c!ma\empty \dosetmathfamily\mbfam\textface\scriptface\scriptscriptface\c!mb\empty \dosetmathfamily\mcfam\textface\scriptface\scriptscriptface\c!mc\empty \dosetmathfamily\nnfam\textface\scriptface\scriptscriptface\c!nn\empty \to \mathstrategies \appendtoks \dosetskewchar\mifam\defaultskewcharmi % implemented later on \dosetskewchar\syfam\defaultskewcharsy % implemented later on \to \mathstrategies \def\dosetskewchar#1#2% {\ifx\@@fontskewchar\empty \skewchar\textfont #1#2% \skewchar\scriptfont #1#2% \skewchar\scriptscriptfont#1#2% \else \skewchar\textfont #1\@@fontskewchar \skewchar\scriptfont #1\@@fontskewchar \skewchar\scriptscriptfont#1\@@fontskewchar \fi} i'll patch the distribution Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------