This is a simple custom workflow which uses a xslt file to modify the record xml, and turn it into a html email.

This means that you have complete control over the email output using xslt, and can send out pretty much any kind of email content.

The complete workflow class:

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;
using System.Xml;
using System.Xml.XPath;

using Umbraco.Forms.Core;
using Umbraco.Forms.Core.Enums;
using Umbraco.Forms.Data.Storage;


namespace XsltEmailWorkFlow
{
    public class SendEmail : Umbraco.Forms.Core.WorkflowType
    {
        [Umbraco.Forms.Core.Attributes.Setting("Email", description = "Enter the receiver email", control = "Umbraco.Forms.Core.FieldSetting.TextField")]
        public string Email { get; set; }

        [Umbraco.Forms.Core.Attributes.Setting("Subject", description = "Enter the subject", control = "Umbraco.Forms.Core.FieldSetting.TextField")]
        public string Subject { get; set; }

        [Umbraco.Forms.Core.Attributes.Setting("XsltFile", description = "Transform the xml before posting it,<a target='_blank' href='xslt/postAsXmlSample.xslt'>(Sample file)</a>", prevalues = "XsltEmail", control = "Umbraco.Forms.Core.FieldSetting.File")]
        public string XsltFile { get; set; }


        public SendEmail()
        {
            this.Id = new Guid("34bca580-f928-11de-8a39-0800200c9a66");
            this.Name = "Send xslt transformed email";
            this.Description = "Send the result of the form to an email addresse";
        }

        public override List<Exception> ValidateSettings()
        {
            List<Exception> l = new List<Exception>();
            if (string.IsNullOrEmpty(Email))
                l.Add(new Exception("'Email' setting not filled out'"));

            if (string.IsNullOrEmpty(Subject))
                l.Add(new Exception("'Subject' setting not filled out'"));
            
            return l;
        }

        
        public override WorkflowExecutionStatus Execute(Record record, RecordEventArgs e)
        {
            System.Net.Mail.MailMessage m = new System.Net.Mail.MailMessage();
            m.From = new System.Net.Mail.MailAddress(umbraco.UmbracoSettings.NotificationEmailSender);
            m.Subject = Subject;
            m.IsBodyHtml = true;

            if (Email.Contains(";"))
            {
                string[] emails = Email.Split(';');
                foreach (string email in emails)
                {
                    m.To.Add(email.Trim());
                }
            }
            else
            {
                m.To.Add(Email);
            }

            RecordsViewer viewer = new RecordsViewer();
            XmlNode xml = viewer.GetSingleXmlRecord(record, new System.Xml.XmlDocument());

            //we will by default set the body to the record xml so if no xslt file is
            //present we atleast get the raw data.
            string result = xml.OuterXml;
            if (!string.IsNullOrEmpty(XsltFile))
            {
                result = Umbraco.Forms.Data.XsltHelper.TransformXML(xml, XsltFile, null);
            }

            m.Body = result;

            System.Net.Mail.SmtpClient s = new System.Net.Mail.SmtpClient();
            s.Send(m);
            
            return WorkflowExecutionStatus.Completed;
        }
    }
}

And a sample xslt file to generate the body html:

<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:msxsl="urn:schemas-microsoft-com:xslt"
xmlns:user="urn:my-scripts"
exclude-result-prefixes="xsl msxsl user"> 

    <xsl:output method="html" media-type="text/html" doctype-public="-//W3C//DTD XHTML 1.0 Strict//EN"
    doctype-system="DTD/xhtml1-strict.dtd"
    cdata-section-elements="script style"
    indent="yes"
    encoding="utf-8"/>
     
    <xsl:param name="records" /> 
   
    <xsl:template match="/">
    
    <h3>Intro</h3>
     <p>
         Hello, this is a sample email using xslt to convert a record into a custom email
      </p>
        
  <h3>the fields</h3> 
      <ul>
            <xsl:for-each select="$records//fields/child::*">
               <li>
                    <h4>Caption: <xsl:value-of select="./caption"/></h4>
                    <p>
                     <xsl:value-of select=".//value"/>
                   </p>
                </li>
           </xsl:for-each>
     </ul>
   
  <h3>The actual xml</h3> 
  <xsl:copy-of select="$records"/>
        
  </xsl:template> 
 
 
 
</xsl:stylesheet> 

When you compile the code and add it to the /bin a new workflow will turn up in the list. When you select it, you can input receiver email, subject and upload an xslt file. The uploaded xslt file transform the record xml.

And you're done