This should be achievable with the list-style-type CSS property. Try out this code below, and see if this is working how you would like:

.name-list {
  list-style-type: upper-alpha;
}

<ol class="name-list">
  <li>Bill</li>
  <li>Steve</li>
  <li>William</li>
</ol>

1. Coffee
1. Java
2. Mocca
3. Tea
4. Milk

I wouldn't mind seeing lettered lists as well. I came here to post the same thing, prompted by my edit (edit #3) here: https://stackoverflow.com/posts/5760019/revisions

The OP attempted to use lettered lists, but the formatting was incorrect. I corrected the list formatting but had to change to numbered lists since there was no support for lettered lists.

Of course, this is fairly minor -- in this case (and in the majority of cases, I believe) the list can still be represented in a semantically correct way by using numbers or bullets instead of letters, so it's no big deal. It would be a nice option to have, though.

You need an ordered list <ol> which by default will order them by numbers.

you can use the type="a" attribute in HTML to change it to lower case letters. Alternatively, you can change it with CSS by adding the following property: list-style-type: lower-alpha;

These are the options an unordered list has:

The important thing is, that a "sub-list" must be still within the parent list point <li>

<ol type="A">
  <li>1st 1st-level list item
    <ol>2nd-level sublist
      <li>1</li>
      <li>2
        <ol type="a">
          <li>must be part of the 2nd main list point</li>
          <li>must be part of the 2nd main list point</li>
          <li>must be part of the 2nd main list point</li>
          <li>must be part of the 2nd main list point</li>
        </ol>
      </li>
      <li>for the 3rd main list point you need to add a new li</li>
    </ol>
  </li>
  <li>2nd 1st level list-item</li>
</ol>

You can use CSS counters and have 1a-1d for each of the lis (the 1 is from the ol counter and the a-d is from the li counter. CSS counters can be configured to show a number of different styles and types.

EDIT - as @Tomalak indicates in the comments - I have amended this to reset the li-index in the ol styles - and added a second list to demonstrate the result. The first list is showing 1a - 1d and the second list is showing 2a - 2d.

I also changed it to an ol structure to closer match the OP's request, but the concept works for any type of list (and any type of repeating element).

.list-wrapper {
    counter-reset: ol-index;
    counter-reset: li-index;
}

ol {
    list-style: none;
    counter-increment: ol-index;
    counter-reset: li-index;
}

ol li {
    counter-increment: li-index;
}

ol li::before {
  content: counter(ol-index) counter(li-index, lower-alpha) ". ";
}

<div class="list-wrapper">
  <ol>
      <li>milk</li>
      <li>bread</li>
      <li>butter</li>
      <li>coffee beans</li>
  </ol>
  <ol>
      <li>paper</li>
      <li>flour</li>
      <li>jam</li>
      <li>biscuits</li>
  </ol>
</div>