This is a bit late in the day for suggesting this, given how long ago the original question was posted, but this is what I did.
I needed a range of 70 years, which, while not as much as 100, is still too many years for the visitor to scroll through. (jQuery does step through year in groups, but that's a pain in the patootie for most people.)
The first step was to modify the JavaScript for the datepicker widget:
Find this code in jquery-ui.js or jquery-ui-min.js (where it will be minimized):
for (a.yearshtml+='<select class="ui-datepicker-year" onchange="DP_jQuery_'+y+".datepicker._selectMonthYear('#"+
a.id+"', this, 'Y');\" onclick=\"DP_jQuery_"+y+".datepicker._clickMonthYear('#"+a.id+"');\">";b<=g;b++)
a.yearshtml+='<option value="'+b+'"'+(b==c?' selected="selected"':"")+">"+b+"</option>";
a.yearshtml+="</select>";
And replace it with this:
a.yearshtml+='<select class="ui-datepicker-year" onchange="DP_jQuery_'+y+
".datepicker._selectMonthYear('#"+a.id+"', this, 'Y');
\" onclick=\"DP_jQuery_"+y+".datepicker._clickMonthYear('#"+a.id+"');
\">";
for(opg=-1;b<=g;b++) {
a.yearshtml+=((b%10)==0 || opg==-1 ?
(opg==1 ? (opg=0, '</optgroup>') : '')+
(b<(g-10) ? (opg=1, '<optgroup label="'+b+' >">') : '') : '')+
'<option value="'+b+'"'+(b==c?' selected="selected"':"")+">"+b+"</option>";
}
a.yearshtml+="</select>";
This surrounds the decades (except for the current) with OPTGROUP tags.
Next, add this to your CSS file:
.ui-datepicker OPTGROUP { font-weight:normal; }
.ui-datepicker OPTGROUP OPTION { display:none; text-align:right; }
.ui-datepicker OPTGROUP:hover OPTION { display:block; }
This hides the decades until the visitor mouses over the base year. Your visitor can scroll through any number of years quickly.
Feel free to use this; just please give proper attribution in your code.