On Mac OS X, you can easily read and write to the preference .plist files using the 'defaults' command. I didn't find anything on parsing the results in Tcl, so I quickly wrote up a script to parse an array of filenames like you'd use to store a "Recent Files" list.

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set domain "recentfilestext"
set key "recentfiles"

catch {exec defaults write $domain $key -array patch.pd another.pd "file with spaces.txt" "file, with,commas.pd" oneword.txt anotherpatch.pd}

if {![catch {exec -- defaults read $domain $key} arr]} {
    puts "arr $arr"
    set filelist $arr
    regsub -all -- {",\s+"} $filelist {" "} filelist
    regsub -all -- {\n} $filelist {} filelist
    regsub -all -- {^\(} $filelist {} filelist 
    regsub -all -- {\)$} $filelist {} filelist
    puts "filelist: $filelist"
    foreach file $filelist {                                                                                           
        puts "file: $file"                                                                                             
    }                                                                                                                  
}
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