You could place your \hrulefill
in \vtop
boxes as below:
\documentclass[10pt,letterpaper]{article}
\begin{document}
Please state your name: \hrulefill
I was born on \hskip-1em\vtop{\vskip.05cm\hsize=2in \hrulefill}%
~~in \hskip-1em\vtop{\vskip.05cm\hsize=2in \hrulefill}
\end{document}

You could do the same thing using a macro:
\documentclass[10pt,letterpaper]{article}
\def\Lrule#1#2{\vtop{\vskip#1\hsize=#2 \hrulefill}}
\begin{document}
Please state your name: \hrulefill
I was born on\hskip-1em\Lrule{.05cm}{2in}~~in%
\hskip-1em\Lrule{.05cm}{2in}
\end{document}
However, the above requires one to specify a line length, and therefore does not act like a \hrulefill
because it has no glue.
A different way of doing it using leaders. This time the control sequence acts like a \hrulefill
but has a variable height relative to baseline (first variable). It uses a repeated character to produce the line (second variable):
\documentclass[10pt]{article}
\def\Vrulefill#1#2{
\leavevmode%
\hskip-.2in%
\leaders%
\vtop{\hsize=.0025in\vskip#1#2}%
\hfill%
\hskip.3in%
}
\begin{document}
%%With Zero \vskip and the period as the repeated character%%
\Vrulefill{0in}{.}Hello Kitty\Vrulefill{0in}{.}Hello Kitty\Vrulefill{.02in}{.}%
Hello Kitty \vskip.1in
%%With Zero \vskip and the \_ as the repeated character%%
\Vrulefill{0in}{\_}Hello Kitty\Vrulefill{0in}{\_}Hello Kitty\Vrulefill{0in}{\_}%
Hello Kitty \vskip.1in
%%With Zero \vskip and the dash as the repeated character%%
\Vrulefill{0in}{-}Hello Kitty\Vrulefill{0in}{-}Hello Kitty\Vrulefill{0in}{-}%
Hello Kitty
\vskip.5in
%%With .05in \vskip and the period as the repeated character%%
\Vrulefill{.05in}{.}Hello Kitty\Vrulefill{.05in}{.}Hello Kitty\Vrulefill{.05in}{.}%
Hello Kitty \vskip.1in
%%With .05in \vskip and the \_ as the repeated character%%
\Vrulefill{.05in}{\_}Hello Kitty\Vrulefill{.05in}{\_}Hello Kitty\Vrulefill{.05in}{\_}%
Hello Kitty \vskip.1in
%%With .05in \vskip and the dash as the repeated character%%
\Vrulefill{.05in}{-}Hello Kitty\Vrulefill{.05in}{-}Hello Kitty\Vrulefill{.05in}{-}%
Hello Kitty
\vskip.5in
%%With negative .05in \vskip and the period as the repeated character%%
\Vrulefill{-.05in}{.}Hello Kitty\Vrulefill{-.05in}{.}Hello Kitty\Vrulefill{-.05in}{.}%
Hello Kitty \vskip.1in
%%With negative .05in \vskip and the dash as the repeated character%%
\Vrulefill{-.05in}{\_}Hello Kitty\Vrulefill{-.05in}{\_}Hello Kitty\Vrulefill{-.05in}{\_}%
Hello Kitty \vskip.1in
%%With negative .05in \vskip and the dash as the repeated character%%
\Vrulefill{-.05in}{-}Hello Kitty\Vrulefill{-.05in}{-}Hello Kitty\Vrulefill{-.05in}{-}%
Hello Kitty
\end{document}
Which produces:

Changing
`\vtop{\hsize=.0025in\vskip#1#2}%
to:
`\vtop{\hsize=.05in\vskip#1#2}%`
gives you some very nice dotted and dashed lines:

and using the same \vtop{\hsize=.05in\vskip#1#2}%
\Vrulefill{0in}{/}
\vskip.2in
\Vrulefill{0in}{@}
\vskip.2in
\Vrulefill{0in}{[]}
\vskip.2in
\Vrulefill{0in}{\}\{}
can produce some interesting decorative rules:

Thick and skinny lines, or dashes, can be made by using a \vline
as the "character":
\Vrulefill{0in}{\vline height .2em width 4pt}
\Vrulefill{0in}{\vline height .001em width 4pt}

xhfill
package