Sure. By collecting the info found in Hugo’s sitemap.xml, How to find days elapsed since last post in a listing page? and How to get a footer with build time?, I think you could use something like this:
{{ printf "<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\" ?>" | safeHTML }}
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:xhtml="http://www.w3.org/1999/xhtml">
{{ range .Site.RegularPages }}
{{ if lt (div (sub now.Unix .Lastmod.Unix) 3600) 48 }}
<url>
<loc>{{ .Permalink }}</loc>{{ if not .Lastmod.IsZero }}
<lastmod>{{ safeHTML ( .Lastmod.Format "2006-01-02T15:04:05-07:00" ) }}</lastmod>{{ end }}{{ with .Sitemap.ChangeFreq }}
<changefreq>{{ . }}</changefreq>{{ end }}{{ if ge .Sitemap.Priority 0.0 }}
<priority>{{ .Sitemap.Priority }}</priority>{{ end }}{{ if .IsTranslated }}{{ range .Translations }}
<xhtml:link
rel="alternate"
hreflang="{{ .Lang }}"
href="{{ .Permalink }}"
/>{{ end }}
<xhtml:link
rel="alternate"
hreflang="{{ .Lang }}"
href="{{ .Permalink }}"
/>{{ end }}
</url>
{{ end }}
{{ end }}
</urlset>